Garage supply

Discussion in 'Electricians' Talk' started by Sprite78, Jan 27, 2019.

  1. Sprite78

    Sprite78 New Member

    Hi All

    I’m looking to change the electrics in my attached garage. Currently there is a one double socket on its own ring main, back to a 32A mcb on the main Consumer unit. Essentially,, taking off the current socket, I’m left with 2 x 2.5 TEtails coming into the garage. It’s about an 11m run.

    It’s not possible to rerun the feed. If it was, I’d run the feed in 4mm.

    Question is.... can I use both lengths of 2.5mm and run them in parallel to a garage CU? To give greater capacity.

    Or should I just use a single length of the 2.5mm feed, and downgrade the mcb’s in the garage Consumer unit to a 20A for sockets (2xdouble socket) and a 6A mob for lights? Based on the fact that cable is only rated to about 25A??
     
  2. spinlondon

    spinlondon Screwfix Select

    You could just leave as is, extend the ring to another socket and use an FCU off the ring for the lights.
    You wouldn’t need to notify for Part P then.
     
  3. retiredsparks

    retiredsparks Super Member

    Separate 2.5 'ring' to a single socket in a garage is odd ?
    Usually a spur at origen off a house ring 32A ..or just a 2.5 Radial on a 20A MCB.
    Double check what you actually have.
    RS
     
  4. Sprite78

    Sprite78 New Member

    Thanks for the advice. It is a ring to a single socket. I know, because it was put in 5 years ago when the garage extension was built, with a view to upgrading and extending in future.

    Out of interest, Would the ring (from 32A main CU) and fcu method for lighting, be compliant if this was a new build/new extension? Also, can a switched FCU be used as the light switch? Or does it need a separate light switch?

    And finally, I want one of the sockets to be an outside socket. Does this change any of the advice? And are there any guidelines on how close an external socket can be to an outside tap?

    Thanks
     
  5. spinlondon

    spinlondon Screwfix Select

    It complies for any kind of build.
    A Switched FCU could be used as a light switch.
    RCD protection is required for all domestic sockets now.
    You don’t want a socket below a water tap.
    Not sure there are guidelines for a distance from an outside tap.
    Guidelines for sockets and kitchen sinks are 300mm.
    The FCU or SFCU will come with a 13A fuse.
    I would recommend changing the fuse to 3A or 5A.
     
  6. Sprite78

    Sprite78 New Member

    Thanks spin London. I think I’ll take the hit on the garage CU I bought and do as you suggest. The main CU which the feed runs off, was replaced 5 yrs ago so it’s all RCD protected.
     
  7. peter palmer

    peter palmer Screwfix Select

    I think you can use 2 cables in parallel to double up on capacity as long as both cables follow the same route. It would have to stay on a 32A MCB and ideally be on a non RCD supply, however if the cable is buried in the plaster anywhere then it needs RCD protection.
     
  8. Sprite78

    Sprite78 New Member

    One last question. Should the cable from the 32a ring, for the light spur be 2.5mm until it reaches the SFCU?
     
  9. spinlondon

    spinlondon Screwfix Select

    No, it doesn't have to be.
     

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